Flapper valve assemblies can be configured to automatically close a vent port in a fuel tank when a fuel level in the tank reaches a predetermined level. To accomplish this, a typical flapper valve assembly may include a flapper member having a sealing surface that seals against a valve seat of the vent port, thereby closing the valve. The quality of the seal, however, can be affected by misalignment of the flapper member relative to the valve seat. For example, such misalignment may occur when the flapper valve assembly is not maintained in a vertical orientation or if the flapper member becomes coaxially misaligned with the valve seat. Further, the quality of the seal may also be affected if the sealing surface of the flapper member sticks to the valve seat before the flapper member properly orients itself relative to the valve seat.
Thus, it would be desirable to provide a flapper valve assembly that is capable of maintaining proper alignment of a flapper member relative to a valve seat and that includes a self-lubricating seal.